Prognostic subclassification of Intermediate Hepatocellular Carcinoma (I-HCC): a multicentre cohort study with propensity score analysis.

e15139 Background: The clinical heterogeneity of I-HCC significantly impacts on management options. Transarterial chemoembolization (TACE) is standard of care, however selected patients may be offered liver resection (LR), whilst others qualify for best supportive care only. The I-HCC subclassification score developed by Bolondi et al. consists of 4 stages and includes the Child-Pugh class, tumour number, size and presence of portal vein thrombosis (Bscore). We evaluated the prognostic effect of the Bscore on overall survival (OS) in a large multicentre retrospective cohort study of patients with I-HCC stratifying by treatment modality (TACE or LR). Methods: Consecutive patients from centres in Japan, Korea, Italy and the UK who underwent TACE or LR between 2001 and 2014 were enrolled (n = 1423). Baseline characteristics were used to derive the Bscore score in I-HCC patients (n = 611). Propensity score matching (PSM) was applied between LR and TACE patients to match on baseline characteristics (age, gender, hepatitis status and INR). Cox regression models with PSM were used to determine the prognostic significance of the 4 stage Bscore in patients treated with TACE (n = 449) versus LR (n = 162), independent of treatment. Results: Among 611 I-HCC patients, 75% were men and 25% women, with a mean age of 69 years and median OS of 37 months. In all I-HCC patients irrespective of treatment Bscore was predictive of OS (p < 0.001). Median OS BScore 1 - 51 months, 2 – 38.3 months, 3 – 24.3 months, 4 -15.6 months. Proportional hazards assumption was met when PSM was applied and Bscore remained significant in predicting OS (n = 483, p < 0.001). When Bscore was stratified in accordance to treatment modality using PSM, Bscore was predictive in treatment with TACE but not LR (p < 0.001 vs. p = 0.047). Conclusions: The Bscore optimizes prognostic prediction in I-HCC, reducing clinical heterogeneity. However, preliminary results suggest its validity is limited to patients undergoing TACE.